JRE 8 rt.jar is the JAR file for JRE 8 RT (Runtime) libraries. JRE (Java Runtime) 8 is the runtime environment included in JDK 8. JRE 8 rt.jar libraries are divided into 6 packages:

com.* - Internal Oracle and Sun Microsystems libraries
java.* - Standard Java API libraries.
javax.* - Extended Java API libraries.
jdk.* -  JDK supporting libraries.
org.* - Third party libraries.
sun.* - Old libraries developed by Sun Microsystems.

JAR File Information:

Directory of C:\fyicenter\jdk-1.8.0_191\jre\lib
      63,596,151 rt.jar

Here is the list of Java classes of the com.* package in JRE 1.8.0_191 rt.jar. Java source codes are also provided.

⏎ com/sun/jmx/snmp/SnmpPdu.java

/*
 * Copyright (c) 2001, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
package com.sun.jmx.snmp;


import java.io.Serializable;
import java.net.InetAddress;
/**
 * Is the fully decoded representation of an SNMP packet.
 * <P>
 * Classes are derived from <CODE>SnmpPdu</CODE> to
 * represent the different forms of SNMP packets
 * ({@link com.sun.jmx.snmp.SnmpPduPacket SnmpPduPacket},
 * {@link com.sun.jmx.snmp.SnmpScopedPduPacket SnmpScopedPduPacket})
 * <BR>The <CODE>SnmpPdu</CODE> class defines the attributes
 * common to every form of SNMP packets.
 *
 *
 * <p><b>This API is a Sun Microsystems internal API  and is subject
 * to change without notice.</b></p>
 * @see SnmpMessage
 * @see SnmpPduFactory
 *
 * @since 1.5
 */
public abstract class SnmpPdu implements SnmpDefinitions, Serializable {

    /**
     * PDU type. Types are defined in
     * {@link com.sun.jmx.snmp.SnmpDefinitions SnmpDefinitions}.
     * @serial
     */
    public int type=0 ;

    /**
     * Protocol version. Versions are defined in
     * {@link com.sun.jmx.snmp.SnmpDefinitions SnmpDefinitions}.
     * @serial
     */
    public int version=0 ;

    /**
     * List of variables.
     * @serial
     */
    public SnmpVarBind[] varBindList ;


    /**
     * Request identifier.
     * Note that this field is not used by <CODE>SnmpPduTrap</CODE>.
     * @serial
     */
    public int requestId=0 ;

    /**
     * Source or destination address.
     * <P>For an incoming PDU it's the source.
     * <BR>For an outgoing PDU it's the destination.
     * @serial
     */
    public InetAddress address ;

    /**
     * Source or destination port.
     * <P>For an incoming PDU it's the source.
     * <BR>For an outgoing PDU it's the destination.
     * @serial
     */
    public int port=0 ;

    /**
     * Returns the <CODE>String</CODE> representation of a PDU type.
     * For instance, if the PDU type is <CODE>SnmpDefinitions.pduGetRequestPdu</CODE>,
     * the method will return "SnmpGet".
     * @param cmd The integer representation of the PDU type.
     * @return The <CODE>String</CODE> representation of the PDU type.
     */
    public static String pduTypeToString(int cmd) {
        switch (cmd) {
        case pduGetRequestPdu :
            return "SnmpGet" ;
        case pduGetNextRequestPdu :
            return "SnmpGetNext" ;
        case pduWalkRequest :
            return "SnmpWalk(*)" ;
        case pduSetRequestPdu :
            return "SnmpSet" ;
        case pduGetResponsePdu :
            return "SnmpResponse" ;
        case pduV1TrapPdu :
            return "SnmpV1Trap" ;
        case pduV2TrapPdu :
            return "SnmpV2Trap" ;
        case pduGetBulkRequestPdu :
            return "SnmpGetBulk" ;
        case pduInformRequestPdu :
            return "SnmpInform" ;
        }
        return "Unknown Command = " + cmd ;
    }
}

⏎ com/sun/jmx/snmp/SnmpPdu.java

Or download all of them as a single archive file:

File name: jre-rt-com-1.8.0_191-src.zip
File size: 8099783 bytes
Release date: 2018-10-28
Download 

⇒ Backup JDK 8 Installation Directory

⇐ JRE 8 rt.jar - org.* Package Source Code

⇑ Download and Use JDK 8

⇑⇑ FAQ for JDK (Java Development Kit)